Signals that can be processed to extract various parameters such as frequency, bandwidth, power, Eb/No, modulation parameters, in-band interferences, etc., are generally limited by a front-end analog-to-digital (A/D) converter, in that the bandwidth of the signals must be smaller than the converter's input bandwidth as well as the A/D sampling rate. This fundamental limitation is dictated by the Nyquist Theorem that states that the A/D sampling rate must be at least twice the signal bandwidth. Furthermore, the signal is also limited by the A/D input bandwidth, such that even if the sampling rate is sufficiently high, the input signal instantaneous bandwidth is still limited by the allowable input bandwidth of the A/D converter.
Therefore, what is needed is a way to increase bandwidth of a signal processing system.